Sexual transmission of HIV-1 parallels FIV in its natural history and pathogenesis. FIV infects domestic and wild felids, causing an AIDS-like disease in cats that closely resembles the clinical and immunological changes observed in HIV-1-infected people. This revised application is designed to develop the FIV model of seminal transmission of HIV-1 based on the hypothesis that semen from FIV+ cats harbors infectious virus. Studies during the first three years of this program will test this hypothesis both in vitro and in vivo, focusing on the type, quantity, kinetics, and source of virus expression in seminal cells and seminal fluid. In the final two years, studies will investigate means to reduce transmission of FIV in semen by physical in vitro modifications of ejaculates, and through administration of antiviral therapy to donor male cats. The candidate, Dr. Holly Jordan, has completed a two-year residency in veterinary clinical pathology, and is currently pursuing a doctorate in immunology with a minor in biotechnology. Her dissertation, to be completed by the summer of 1997, will examine seminal transmission of FIV. Throughout her post-DVM training, Dr. Jordan has conducted research with a variety of animal species in both clinical and research applications, and has presented this work through publications and abstracts. As a veterinary clinical pathologist and immunologist, she is committed to a research career in comparative medical science at a research institution. The primary sponsor, Suzanne Kennedy-Stoskopf, DVM, PhD, has extensive experience in comparative retrovirology and immunology. The Secondary Sponsor and graduate advisor, Wayne Tompkins, PhD, will provide guidance and support, particularly during the first three years of this program. The Collaborator, JoGayle Howard, DVM, PhD, at the National Zoological Park, Smithsonian Institution, will provide expertise in feline reproductive physiology. The NCSU College of veterinary Medicine maintains intensive interdisciplinary training through the Biotechnology Program, seminars, rounds, and journal clubs. Additional research experience in feline reproductive techniques will be obtained periodically during the first year of this project through the National Zoological Park.